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VISCOMETRIC INVESTIGATIONS OF POLYVINYLPYRROLIDONE IN MIXED SOLVENTS AND WITH VARYING TEMPERATURE

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Chinese Journal of Polymer Science 2005年第4期23卷 367-371页

作者： omar Melad omar Abu-Tiem Rajai Baraka Chemistry Department

The viscosity behavior of polyvinylpyrrolidone(PVP)has been determined at 25℃ in mixed solvents comprising water/dimethylformamide(DMF)and water/methanol(MeOH).Analysis of the data has considered the PVP as being both host and guest polymer in *** intrinsic viscosity of PVP in DMF is higher than in water and in MeOH,but also increases in a mixed solvent with high water content because of the effect of polymer-solvent *** was also found that the intrinsic viscosity of PVP at finite concentration,[η_(pvp)]_c decreases with an increase in the concentration of PVP in *** viscosity behavior of PVP in a mixed solvent is affected by the concentration-dependent intermolecular excluded volume effect,which can be quantitatively expressed by the parameter,b_Y,which reflects the shrinkage of PVP chain coils,resulting in a decrease of[η_(pvp)]_*** effect of temperature on the viscosity behavior of PVP in MeOH shows that the interaction parameter increases up to a maximum value,and then decreases after a certain temperature.

关键词： Polyvinylpyrrolidone Intermolecular excluded volume effect Intrinsic viscosity

Case Report: Rhupus (The Association of Systemic Lupus Erythematosus and Rheumatoid Arthritis): About 2 Cases

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Open Journal of Rheumatology and Autoimmune Diseases 2024年第2期14卷 84-88页

作者： omar Boun Khatab Diouf Mouhamed Dieng Michel Assane Ndour Matar Ndiaye Nousradine Mourno Tarsa Boundia Djiba Ibrahima Mané Diallo Demba Diedhiou Anna Sarr Maimouna Ndour Mbaye Internal Medicine Departement Abass Ndao Hospital Dakar Senegal

Introduction: The association of systemic lupus erythematosus and rheumatoid arthritis (rhupus) is a rare clinical condition. Throughout the world, 287 cases of Rhupus have been described. We report two new observations of two patients who presented predominantly distal erosive polyarthritis with positive anti-Sm antibodies in one case and SmRNP in the other case. Observations: Case 1: 37 years old patient, with a recent diagnosis of pulmonary tuberculosis. She has since 8 months an inflammatory, bilaterally and symmetrical polyarthralgia without deformation or ankylosing synovitis, associated with malar erythema without other abnormalities. Immunological tests showed: positive Rheumatoid factor at 158 IU/ml, positive Anti-CCP at 550 IU/ml, and positivity of antinuclear at 1/1280 nuclear fluorescence with a strong presence of anti-Sm >8 IU/ml. The diagnosis of rhupus was concluded, without serious visceral involvement. Case 2: A 28-year-old patient, married with 3 children, with bilateral, symmetrical, deforming and chronic polyarthritis affecting large and small joints, which had been evolving for over 5 years without cutaneous abnormality associated. Paraclinical investigations showed: a biological inflammatory syndrome. Immunology was positive, with rheumatoid factors at 78 IU/ml, anti-CCP at 561 IU/ml, antinuclear antibodies at 1/1280 with positive anti-SmRNP and anti-SSA/Ro52, and a positive direct Coombs test. Joint ultrasound revealed tenosynovitis of the extensors and common flexors of the fingers, erosions and synovitis of multiple PPIs. The diagnosis of rhupus was based on the presence of 10 ACR criteria for RA and 8 ACR/EULAR 2019 criteria for SLE. Conclusion: Rheumatoid arthritis is a rare autoimmune disease combining features of both systemic lupus erythematosus and rheumatoid arthritis in the same patient, often sequentially. Despite a growing number of case reports and series, a consensus on the classification of SLE arthritis is still lacking, and di

关键词： Rhumatoïd Arthritis Lupus Rhupus Connective Tissue Disease

Reintegrating nanogranitoid inclusion composition to reconstruct the prograde history of melt-depleted rocks

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Geoscience Frontiers 2019年第2期10卷 517-525页

作者： omar Bartoli Department of Geosciences University of Padova

A recent fascinating development in the study of high-grade metamorphic basements is represented by the finding of tiny inclusions of crystallized melt(nanogranitoid inclusions) hosted in peritectic phases of migmatites and granulites. These inclusions have the potential to provide the primary composition of crustal melts at the source. A novel use of the recently-published nanogranitoid compositional database is presented here. Using granulites from the world-renowned Ivrea Zone(NW Italy) on which the original melt-reintegration approach has been previously applied, it is shown that reintegrating melt inclusion compositions from the published database into residual rock compositions can be a further useful method to reconstruct a plausible prograde history of melt-depleted rocks. This reconstruction is fundamental to investigate the tectonothermal history of geological terranes.

关键词： Nanogranitoids Melt-reintegration Granulite High-temperature metamorphism

Overview of Adrenals Tumors in Dakar Hospitals

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Open Journal of Internal Medicine 2024年第2期14卷 141-150页

作者： Nafy Ndiaye Yakham Mohamed Leye Mouhamadou Moustapha Ndong Ngoné Diaba Diack Amadou Fall Cisse Abdoulaye Leye Baidy Sy Kane Alpha omar Touré Cherif Mohamed Dial Pape Saloum Diop Internalmedeccine and Endocrinology Department Teaching Hospital of Pikine Dakar Senegal General Surgery Department Aristide Le Dantec Teaching Hospital of Dakar Dakar Senegal Anatomo-Pathology Department General Hospital of Grand Yoff Dakar Dakar Senegal General Surgery Department General Hospital of Grand Yoff Dakar Dakar Senegal

Introduction: Adrenal tumours (AT) are commonly encountered in clinical practice. For any patient presenting an adrenal mass, there are two crucial points to consider: is the adrenal mass malignant and is it hormonally active? The objective of our study was to evaluate the epidemiological, diagnostic, therapeutic, and evolutionary aspects of AT in a developing country. Methodology: We conducted a retrospective study spanning 17 years (from January 2005 to October 2022) in four Dakar hospital services. We included all patient medical records with explored AT. Results: AT was diagnosed in 35 patients who had a mean age of 36.62 years (range: 12-79), and a female predominance (26 women to 9 men). Among these patients, 17.2 % had incidental AT. Hypertension was the commonest presenting symptom in 27 patients (77%), which was associated with Mnards triad in 14 patients (40%). Abdominal pain was reported by 20 patients (57%), and 14 presented with an abdominal mass. Among the patients, 29 had functional AT: 22 with pheochromocytoma, 5 with primary hyperaldosteronism, and 2 with hypercortisolism. Imaging evaluations revealed that 33 patients had unilateral AT and one had bilateral AT. Tumour sizes varied, 5 patients had tumours 10 cm. Two patients presented with metastases. The therapeutic approach involved adrenalectomy in 32 patients. Perioperative complications were observed in five patients, including haemorrhage (two patients), hypotension (two cases), and hypertensive crisis (one case). One patient with bilateral pheochromocytoma developed acute adrenal insufficiency postoperatively, followed by abdominal herniation. Histopathological examination confirmed pheochromocytoma in 21 patients, Conns adenoma in 5, adrenocortical carcinoma in 3, cortisol adenoma in 2, and adrenal cyst in 1 patient. Non-functional AT included adrenocortical carcinoma (three patients), adrenal cyst (one patient), and pheochromocytoma (two patients). After a one-year follow-up, 29 patients wit

关键词： Tumour Adrenal Pheochromocytoma Conn Adrenocortical Carcinoma Dakar

Extension of Chemoprevention of Seasonal Malaria to Five Cycles and to Children from the Age of 6 to 9 Years in Africa: Analysis of Its Acceptability, Feasibility, Cost and Impact A Systematic Review

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Advances in Infectious Diseases 2024年第1期14卷 74-86页

作者： N’Kpingou Théodore Nadakou Moussiliou Noel Paraïso Ounoussa Tapha Mahamane Moustapha Lamine Jean Blaise Yobo Salifou Ibrahim Alkassoum Fidel Tossou Hamidou Ramatoulaye Lazoumar Eric omar Adehossi Regional Instutte of Public Health University of Abomey-Calavi (UAC) Ouidah Benin Pratical Institute of Public Health (IPSP) Niamey Niger Andre Salifou University of Zinder (UAS) Zinder Niger ABDOU Moumouni University of Niamey (UAM) Niamey Niger Medical and Health Researche Center (CERMES) Niamey Niger

Introduction: Seasonal Malaria Chemoprevention (SMC) aims at preventing malaria in children during the high transmission season. It has been recommended by the WHO since 2013 for children from the age of 3-59 months. However, despite the impact of this intervention, a peak in the prevalence and incidence of malaria is observed in children from the age of 5-9 years. The aim of this study is to determine from the current literature the feasibility, impact and cost-effectiveness of extending SMC to five cycles and to older children. Methods: A litterature search of PubMed/Medline, NCBI and Google scholar identified 1333 articles. After reading the titles and abstracts by two authors, 24 articles were selected and submitted for full reading. Random control studies on the extension of SMC, malaria, feasibility of SMC, impact of SMC and cost-effectiveness of SMC were selected. A total of 16 articles were included for the qualitative synthesis after excluding 8 studies. Results: Following the summary of the evidence, we conclude that the extension is feasible but will be confronted with the unavailability of older children. The intervention period coincides with field work. SMC is effective in reducing the prevalence and incidence of malaria and the parasite density in children. The financial cost of administering SMC is lower than that of treating a child suffering from malaria. Conclusion: After analysing the information, it was found that the majority of the African population supports the extension of the SMC to the number of cycles and the age group in order to alleviate the high mortality and morbidity rates among children due to malaria.

关键词： SMC Feasibility Impact Profitability and Africa

Enhance Vertical Handover Security During Execution Phase in Mobile Networks

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Computers, Materials & Continua 2022年第8期72卷 3863-3875页

作者： omar Khattab Department of Computer Science and Engineering Kuwait College of Science and Technology(KCST)Kuwait

The Vertical Handover(VHO)is one of the most vital features provided for the heterogeneous mobile *** allows Mobile Users(MUs)to keep ongoing sessions without disruption while they continuously move between different Radio Access Technologies(RATs)such as Wireless Fidelity(Wi-Fi),Global System for Mobile Communication(GSM),Universal Mobile Telecommunications System(UMTS),Long Term Evolution(LTE)and Fifth Generation(5G).In order to fulfill this goal,the VHO must comply to three main phases:starting of collecting the required information and then passing it for decision phase to obtain the best available RAT for performing VHO by execution phase ***,the execution phase still encounters some security issues which are exploited by hackers in launching malicious attacks such as ransomware,fragmentation,header manipulation,smurf,host initialization,reconnaissance,eavesdropping,Denial of Service(DoS),spoofing,Man in the Middle(MITM)and *** paper thoroughly studies the recent security issues for hundreds VHO approaches found in the literature and comes up with a secure procedure to enhance VHO security during execution phase.A numerical analysis results of the proposed procedure are effectively evaluated in terms of security and signaling *** with the recent related work found in literature,the analysis demonstrates that the security is successfully improved by 20%whereas signaling cost is maintained as in non-proposed procedure.

关键词： Vertical handover security mobile networks wireless networks heterogeneous wireless networks

Power Reallocation and Complexity Enhancement for Beyond 4G Systems

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China Communications 2019年第6期16卷 114-128页

作者： omar Daoud Communications and Electronics Engineering Department Philadelphia University

Competitiveness in the modern wireless systems’provided services is a key factor in the development,in addition to the adaptation to/harmonization of user ***,this paper discussed the quality of services from the point of view of the need for supporting the needed data *** this purpose,a benchmark based on Multi-Antenna Multiband Orthogonal Frequency Division Multiplexing has been proposed to compatible with Ultra-Wideband systems such as the fifth generation based *** order to enhance the system quality of service,the structure of the ultra-wideband system’s main stage;namely Orthogonal Frequency Division Multiplexing has been modified by imposing a low complexity designed Haar-wavelets stage instead of the fast Fourier transform *** is in addition to reallocate the transmitted power in order to reduce the effect of one of the main drawbacks that is found in the Orthogonal Frequency Division Multiplexing;namely the peak-to-average power ratio problem.A MATLAB simulation has been performed in order to validate the propositions that have been made based on six different performance *** a result,the new propositions were achieved our targets by reducing the system’s complexity in terms of mathematical operations and by giving promising results in managing the transmitted ***,the effectiveness of such work has been verified and compared with four different work in the literature。

关键词： multi antennas-multiband wireless PAPR Haar-DWT power reallocation ACLR EVM

A Dynamic Management Scheme for Internet of Things(IoT)Environments:Simulation and Performance Evaluation

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Computer Modeling in Engineering & Sciences 2022年第12期133卷 673-695页

作者： omar Said Department of Information Technology College of Computers and Information TechnologyTaif UniversityP.O.Box 11099Taif21944Saudi Arabia

In recent years,the Internet of Things(IoT)technology has been considered one of the most attractive fields for researchers due to its aspirations and implications for society and life as a *** IoT environment contains vast numbers of devices,equipment,and heterogeneous users who generate massive amounts of ***,things’entry into and exit fromIoT systems occur dynamically,changing the topology and content of IoT networks very ***,managing IoT environments is among the most pressing *** paper proposes an adaptive and dynamic scheme for managing IoT environments is *** management scheme depends on the use of previous management methodologies,considering two main *** first factor is network status,which is determined in *** second factor is a management method’s suitability according to its desired *** test the proposed management scheme,a simulation environment is created using *** metrics used to measure the management scheme performance are bandwidth consumption,energy consumption,packet loss,throughput,delay,usage rate of individualmanagement techniques,and *** simulation results prove that the proposed management scheme outperformed the individual 6LowPANSNMP,CoAP,and LWM2M management schemes.

关键词： Internet of Things IoT management IoT simulation SNMP neural networks big data

Seroprevalence of SARS-COV-2 Exposure among “High-Risk” Populations (Healthcare Workers, People Who Attend Markets, and School Children) in Zanzibar

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Advances in Infectious Diseases 2024年第1期14卷 34-55页

作者： Ame Masemo Solomon Mwakasungula Khamis Kheir Erick Mgina Nahya Khamis Irabi Kassim Bihila Bakar Khamis Salim Sarah Mswata Kibwana omar Theckla Kazimoto Linzy Elton Honorati Masanja Mayassa Ally Zanzibar Health Research Institute Binguni Zanzibar Ifakara Health Institute Bagamoyo Tanzania National Institute for Medical Research Muhimbili Centre Dar es Salaam Tanzania Binguni Public Health Laboratory Binguni Zanzibar Department of Microbiology Mnazi Mmoja Hospital Stone Town Zanzibar Centre for Clinical Microbiology Royal Free Hospital Campus University College London London UK

In Zanzibar, from the start of the pandemic in March 2020 to the time of sampling in December 2020, SARS-CoV-2 seroprevalence data was limited. We conducted a seroprevalence study to evaluate the magnitude of SARS-CoV-2 exposure among healthcare workers, school children, and people who attended general markets in Zanzibar. The objectives of the study were to analyse the total antibodies from selected higher-risk population groups in order to determine magnitude in SARS CoV-2 exposure. Blood samples were collected from eligible and consented participants (adults and children), and their serum was analyzed for total antibodies against SARS-CoV-2 using ELISA. A questionnaire was used to collect participants’ demographic and clinical data. The overall SARS-CoV-2 seroprevalence across all age groups was 33%, and a higher seroprevalence was observed in the 40 - 49 years’ age group relative to other ages as well as in those who attended markets. A runny nose (18.8% of participants) was the most frequently reported SARS-CoV-2 infection-related symptom. Multivariable analysis showed significantly higher odds of infection in people living in urban districts. The findings provide insight into SARS-CoV-2 infection among school children, health workers, and people who attended markets in Zanzibar in the early stages of the pandemic. Exposure in these groups might have been influenced by infection and prevention strategies taken by the government, as well as shopping behavior, school overcrowding, and population density in urban settings. The study had methodological limitations, including cross-sectional design. Further, well-designed, longitudinal studies are recommended to understand exposure and transmission at a population level.

关键词： SARS-CoV-2 Seroprevalence Zanzibar ELISA COVID-19